1. Field of the Invention
The present invention relates to a display using an amorphous oxide for an active layer of a transistor.
2. Related Background Art
In recent years, flat panel displays (FPD's) have been put into practical use owing to the progress of a technique for a liquid crystal, electroluminescence (EL), or the like.
Those FPD's are each driven by an active matrix circuit of a field effect thin film transistor (TFT) using an amorphous silicon thin film or a polycrystalline silicon thin film arranged on a glass substrate for an active layer.
Meanwhile, attempts have been made to use a resin substrate having a light weight and flexibility instead of a glass substrate for reducing the thickness and weight of each of those FPD's and for improving the resistance to breakage thereof.
However, the production of a transistor using the above-described silicon thin film requires a step of heating at a relatively high temperature, so it is generally difficult to directly form the silicon thin film on a resin substrate having low heat resistance.
In view of the foregoing, the development of a TFT using an oxide semiconductor thin film made of, for example, ZnO that can be formed into a film at a low temperature has been vigorously conducted (JP 2003-298062 A).
Meanwhile, no technical level to develop an applied technology of a conventional TFT using an oxide semiconductor thin film has been achieved probably because the TFT has no sufficient properties comparable to those of a TFT using silicon.